Someone cited citations I used without citing my work and effort in finding the references

No, this is not plagiarism, unless the authors specifically used the same wording as you. Citing the same sources as another paper is not plagiarism, otherwise anyone who cites an influential paper would be guilty of plagiarism unless they also cited the hundreds of other papers who also cited that influential paper.

In your specific case, you say

Out of the 6 examples 4 are exactly the same in my publication with 3 of them using the same exact citations I used. Which made me believe with zero doubt that the one of the conference paper authors read my workshop paper and found those applications and citations useful and decided to reuse them in their publication without giving my work proper citation for finding those references.

This is speculation, and you can not know that this is indeed what happened. It is also quite likely that the authors did a literature review or simply knew parts of the literature, and found examples of applications that were relevant for their paper. Using the "exact same citations" is what is supposed to happen when you cite the same work.

Unless your paper is relevant and related to the work done in their paper, there is no reason for them to cite your paper, and citing work that is related to both your papers can not be considered plagiarism. At worst, you could argue that the authors should have included your paper in their related work.

Remember, people cite your papers for the work that you describe in that paper, not for the citations you give.

Who cares whether this is technically plagiarism or not? This is obviously a trivial matter and you should not waste your time on it. Do not be overly sensitive on receiving credit for every bit of work you ever did.

Addressing the focal point first:

(1) The editor doesn't believe this is a case of plagiarism. If you want to establish it as one, you will need very strong evidence. Based on the question, I don't think you have that. What you do have is a strong indication that someone has read your paper (this comes from the 4/6 applications bit). There is a weaker indication that your paper has directed the author to further work in the field. But your paper is not the only source for this direction, so this remains a weak and unsubstantial argument.

(2) A researcher may read many publications, and may benefit from them directly or indirectly; but not every one of these will be cited. Citations are for when you use someone's work (results, conclusions, methodology, figures, entire sentences), or when you compare your results to someone, and so on. It is certainly good practice to cite papers which direct you to seminal work, since they saved you effort. But this decision is still up to the author. You may disagree with the decision, but you can't enforce anything.